According to I Make Projects, this handy item can be used for many things; however

most notably uses include just for fun (toss one into a sleeping roommate's bedroom, for example) or use them on the honor-system to enhance any wargames you might play - like laser tag, Airsoft, Nerf, or even Paintball. (If one "goes off" next to you, you're out.)

The pin can be reinserted for innumerable "blasts" of sound. Also, you can make the medicine bottle grenade or the deluxe grenade, depending on your personal preferences. Tossing the roommate the deafening Tylenol grenade the morning after a long night at the bar might be an interesting experiment...

As it happens, Robert Heinlein was also interested in the idea of grenades that did something other than simply explode. In his 1959 novel Starship Troopers, Heinlein talks about talking bombs that speak an alien language (to creatures called "skinny's"):

This was a special bomb, one issued to each of us for this mission with instructions to use them if we found ways to make them effective. The squawking I heard as I threw it was the bomb shouting in skinny talk (free translation): "I'm a thirty second bomb! I'm a thirty second bomb! Twenty-nine! Twenty-eight! Twenty-seven!..."

Readers should be aware that this same novel contains the first reference to amplified muscle exoskeletons (as far as I know), and yes, it was the source material for the Starship Troopers movies. Thanks to reader Diego Rosales for the tip and the sf reference for this story. Find out more at the sonic grenade project page; lots of detailed pix, instructions and demo videos.

Scroll down for more stories in the same category. (Story submitted 4/3/2006)